DE10245798B4 - Electrically operated charge air compressor with integrated air cooling - Google Patents

Abstract

Electrically operated charge air compressor with a housing (12), with at least one compressor wheel (30) arranged in a compressor chamber (28) of a first housing part (14), which in the direction of flow between an air inlet (24) and an air outlet (43) of the housing (12 ) is arranged, with a flow channel (42) connecting the compressor chamber (28) with the air outlet (43) and running in the circumferential direction of the first housing part (12), and with an electric motor arranged in a second housing part (16) of the housing (12) (18) for operating the compressor wheel (30), characterized in that the flow channel (42) at least partially encompasses the electric motor (18) in the axial direction and is in thermal connection with the electric motor (18) and the second housing part (16), wherein the second housing part (16) has a diffuser ring (19) which forms part of the boundary of the flow channel (42) and is thermally coupled to the electric motor (18) is.

Description

State of technology

The invention relates to a device for the compression of combustion air, especially one electrically operated charge air compressor with the features of the generic term of claim 1.

It is known the power density an internal combustion engine by compressing the combustion of the Fuel needed Increase air using an exhaust gas turbocharger. The exhaust gas turbocharger points thereby a turbine on the exhaust gas flow of the internal combustion engine is arranged and the one in the charge air supply of the internal combustion engine arranged compressor drives.

Such turbochargers have the well-known disadvantage of a delayed and inadequate response at low engine speeds ("turbocharger hole").

To improve the charge air supply, especially in the low engine speed range, it is known the exhaust gas turbocharger by means of an electrical auxiliary drive support. This can be done, for example, by an integrated in the exhaust gas turbocharger Electric motor can be reached. The electric motor then drives the shaft of the exhaust gas turbocharger compressor at low engine speeds Internal combustion engine. Such a hybrid drive of the exhaust gas turbocharger requires both a high speed load capacity of the electric motor and also a high electrical power requirement due to the high Moments of inertia the necessarily heat-resistant, steel running Turbine of the exhaust gas turbocharger. It also enlarges the installation volume of such an exhaust gas turbocharger through the integration of the additional The electric motor.

To avoid the disadvantages of such a hybrid drive, it is for example from the US 6,029.45 A known to operate a separate, purely electrically operated auxiliary charger (additional electric compressor, EZV) in the charge air supply of an internal combustion engine in series with a conventional, turbine-driven exhaust gas turbocharger. This has the great advantage that the additional electrical compressor, which is used separately for the charge air supply, can be optimized for short-term use in the lowest speed range of the internal combustion engine. Typically, the additional electrical compressor is connected upstream of the exhaust gas turbocharger, so that the achievable boost pressure is the product of the individual pressure values.

Due to the short-term, very high-speed operation of the additional electrical compressor, this system component is subjected to high thermal loads. In addition to the passive dissipation of the excess heat, it is known to cool the additional electrical compressor during operation by means of the charge air drawn in itself. For active air cooling, the US 5,904,471 A proposed to first conduct the sucked-in air flow along the motor housing or directly through the motor housing and then to feed it to the compressor chamber of the additional compressor. The arrangement of the compression wheel on the side of the driving engine opposite the intake opening and the passage of the air flow through the engine itself results in increased flow resistance for the passive charge air compressor. Such a system has the disadvantage of lower efficiency, which can be achieved for the boost pressure

In the area of high engine speeds, which at the same time leads to a high speed of the exhaust gas turbocharger and associated with a high throughput of charge air alone the promotional effect of the exhaust gas turbocharger, becomes a bypass solution used to bypass the charge air bypassing the additional compressor which is then no longer required feed directly to the compressor of the exhaust gas turbocharger. It is therefore necessary that the additional electrical compressor is in passive operation preferably low flow resistance the charge air drawn in by the exhaust gas turbocharger.

From the US 5,904,471 A is known to integrate a bypass channel in the additional electrical compressor. In the US 5,904,471 A a flap valve is used, which redirects the charge air flow into the bypass duct so that it is not routed through the compression chamber and the compressor wheel of the electrically operated turbocompressor arranged therein. However, such a flap-controlled bypass solution is not optimal with regard to the fluidic requirements for the additional compressor and, taking into account the requirements for assembly, size and costs of the overall system for charge air compression, is very complex and expensive.

In particular, a bypass solution according to the US 5,904,47 A Increased flow resistances in the additional compressor, because, among other things, corners and edges are present in the flow channel due to the designed flap valve, which lead to turbulent flow conditions.

From the DE 41 06 130 A1 a blower driven by an electric motor with a spiral-shaped housing is known, the spiral housing being metallic at least in the region of the spiral inlet and having cooling fins running parallel to the air flow on the inside of this inlet region. The housing accommodating the control or regulating electronics of the blower is in a heat-sealed connection with the part of the spiral housing of the blower that contains the cooling fins.

From the DE 196 06 487 A1 a blower driven by an electric motor is known, in which the driving electric motor is inserted into a housing part of the blower in such a way that the motor is thermally operatively connected to the flow channel of the blower. In this way, the electric motor is also cooled by the air flow of the fan sucked into the flow channel.

The object of the invention is a to further develop additional electric compressors that it cools its air both in active and in passive operation Components with as much as possible low flow resistance allows.

The basis of the invention The task is achieved by a device for compressing combustion air solved with the features of claim 1. Advantageous further training and embodiments result from the features listed in the subclaims.

Advantages of invention

The electrically driven according to the invention Charge air compressor with the features of claim 1 avoids the disadvantages occurring in the prior art and enables an electric turbocompressor in the charge air supply of an internal combustion engine to operate in series with, for example, an exhaust gas turbocharger, the additional compressor according to the invention is air-cooled in both active and passive operation. Advantageously becomes air cooling avoiding an elevated flow resistance of the additional electric compressor.

The compression device according to the invention of combustion air has a housing with a first housing part on in the at least one compressor wheel in a compressor room of the housing is arranged, which in the flow direction between an air inlet and an air outlet of the housing is arranged. Furthermore points the case of the additional compressor according to the invention a second housing part on, in which an electric motor for operating the compressor wheel is arranged is. The fact that a connecting the compressor chamber with the outlet duct in the circumferential direction of the housing running flow channel at least partially encompasses the electric motor is a thermal one Coupling between the compressed charge air flow and the compressor driving electric motor possible.

Advantageous further training and embodiments the invention are made possible by the features contained in the subclaims.

The flow channel of the compressed Charge air is such in the additional compressor according to the invention configured that a thermal coupling between the flow channel and the electric motor or between the flow channel and the electric motor receiving, second housing part consists.

The second is advantageous housing part at least partially made of a heat-conducting material, for example formed from a metal.

A compact and very good heat-conducting embodiment of the additional compressor according to the invention arises when the flow channel essentially formed in the second housing part itself is. In the additional electrical compressor according to the invention it becomes helical trained connecting channel between the compressor chamber of the compressor and the outlet opening to the compressor the embodiments of the prior art in the direction of the driving electric motor "folded over". The hanging, i.e. around the case of the drive wound volute (compressor screw) for one optimal cooling of engine and electronics. Experience has shown that flow formation is particularly favorable the air-guiding housing by a straight line, i.e. axial inlet and a helical, on the circumference of the housing arranged outlet marked.

In a particularly advantageous embodiment of the additional compressor according to the invention is the flow channel (Volute) part of the metallic engine case. The high air mass flow through the volute in both active and passive operation of the additional compressor ensures optimal cooling of the metal body, by the drive motor for the compressor is housed. In addition to the driving electric motor can in the motor housing additionally a compartment can also be formed which contains electronic components to be cooled contains the motor or compressor control.

This advantageously has motor housing a smaller diameter than the inner diameter of the circumference of the compressor housing arranged flow channel. In this way it is possible the electric motor or the housing receiving the electric motor from flow channel at least partially enclose in the axial direction without the construction volume of the compressor according to the invention additionally to enlarge.

The very compact size of the additional compressor according to the invention also results from the fact that the flow channel is arranged on the high-pressure side of the compressor wheel. In particular, the flow channel (volute) can be arranged on the side of the compressor wheel facing away from the inlet channel. This configuration of the flow channel enables effective air cooling of the compressor housing or of the electric motor driving the compressor wheel, without a special flow deflection for the cooling effect being necessary. Rather, the optimized flow guidance in the form of a helical volute can also be used advantageously for cooling the housing.

The flow resistance of the additional compressor according to the invention also in passive operation, i.e. with the electric motor switched off, if possible to keep it low, the compressor according to the invention has a bypass channel on the compressor's inlet duct directly with the flow duct (Volute) connects. The fact that the flow channel over the bypass channel with the Inlet duct of the housing is connectable, enables Shaping according to the invention of the flow channel A great cooling effect even in passive operation. Therefore, advantageously can in the additional compressor according to the invention one and the same flow channel in both active and passive operation for cooling of the component. In the passive mode, the the vast majority Represents the operating mode of the additional electric compressor, it only has the task of keeping the air flow as low as possible flow resistance to let happen. The component can block the air flowing past use yourself for the next Bet on one if possible bring lower operating temperature.

Advantageously, the Compressor according to the invention Means on the bypass channel Close the activated electric motor. A simple and reliable way to close the bypass channel consists of the swirl of the air flowing radially out of the compressor wheel to use to over for example, blades arranged in the diffuser of the compressor to close the bypass channel. The bypass duct is connected to the inlet duct of the Compressor facing side, as well as on its, the flow channel (volute) closed side closed. By closing the flow channel Air turbulence at the inputs of the Bypass channel and thus an increased flow resistance realize in the active operation of the compressor.

The device according to the invention also has Means, especially elastic means, on the bypass channel with the electric motor deactivated if possible open quickly and reliably. by virtue of the great Flow area of the bypass channel is the additional compressor according to the invention in the passive Operating case represents only a very low flow resistance. This also enables in passive operation of the additional compressor a favorable Efficiency of the overall system of the charge air supply or the internal combustion engine.

The claimed device for Compression of combustion air enables an electrically driven Additional compressor for the charge air of a motor vehicle, the efficient cooling, in particular a cooling made possible by the sucked-in charge air, without increased air resistance display. The fact that the air cooling in both active and is also possible in passive operation of the electric charge air compressor and in an advantageous manner through the same flow channel, the thermal load for such a high-speed, electric auxiliary compressor be kept low.

Further advantages of the device according to the invention are in the following drawings and the associated description of an embodiment an inventive device for Compression of combustion air.

In the drawing there are two exemplary embodiments a device according to the invention shown for the compression of combustion air, which in the following description explained should be. The figures of the drawing, their description as well the claims directed towards it contain numerous features in combination. Becomes a professional consider these features individually and make meaningful, further ones Combine combinations.

Show it:

1 2 shows a cross section through an electrically operated charge air compressor according to the invention in a schematic representation,

2 3 shows a cross section through an alternative embodiment of a charge air compressor according to the invention with the bypass duct closed,

3 a cross section through the charge compressor 2 when the bypass channel is open.

description of the embodiments

1 shows a schematic representation of a first embodiment of the inventive device for compressing combustion air. The compressor 10 has a housing 12 on which in the embodiment of the 1 is formed in several parts. The housing of the compressor essentially comprises a first housing part 14 for the actual compressor head 22 the device hereinafter also called the compressor part of the device and a second housing part 16 , which surrounds the drive means for the compressor and in the embodiment of the 1 essentially an electric motor driving the compressor 18 includes the associated electronic components. The second housing part 16 of the compressor according to the embodiment of the 1 is made up of three parts for manufacturing reasons. The housing part 16 includes the actual motor housing 17 of the driving electric motor 18 , which is designed as a pole pot or as a tube, a diffuser ring 19 , which lies in the axial direction between the compressor head 22 and the motor housing 17 is arranged and a third housing part 15 which is a compartment 52 for electronic components for controlling the compressor and part of the flow channel of the compressor.

In addition, the housing 12 one the housing part 16 occlusive bottom 20 on which allows easy access to the motor part of the device and also supports a bearing of the drive shaft of the compression wheel.

The compressor head 22 of the compressor 10 is designed as a radial compressor with axial suction. The first housing part 14 for the compressor head 22 has a bell-shaped or funnel-shaped configuration with an inlet channel 24 passing through an inlet port 26 of the first housing part 14 is formed.

In the first part of the housing 14 is a compressor room 28 trained in which a compressor wheel 30 is arranged. The compressor wheel 30 is concentric to the inlet duct 24 of the first housing part 14 of the compressor 10 arranged. The compressor wheel 30 has a flat bottom 32 on which the second housing part 16 of the compressor 10 and especially diffusoring 19 is facing. The one from the bottom 32 of the compressor wheel 30 top of the compression vane facing away is in a manner known per se with compression structures 34 provided in the form of three-dimensional blades. From the inlet duct 24 of the compressor 10 a first flow channel extends 36 in the axial direction of the compressor into the compressor chamber 28 , That through the first flow channel 36 Charge air sucked in during operation of the compressor is discharged through the compressor wheel 30 accelerated and pushed radially outwards. At its radial ends 38 the compressor room goes 28 in a radial diffuser 40 about. The radial diffuser 40 again opens into a flow channel 42 , which is a snail continuously on the circumference of the housing 12 expands and acts as a collector for the compressed charge air. At the point where the helical flow channel 42 ("Volute") hits its beginning in the circumferential direction of the compressor, the flow channel goes 42 tangential to the housing 12 of the compressor away. The radial diffuser 40 also ends tangentially in the flow channel 42 , The diffuser ring 19 , which is thus on the compressor wheel 30 facing top the air from the compressor wheel into the flow channel 42 transferred, is simultaneously cooled by this air. It forms together with the underside of a control hood 60 For a bypass channel of the compressor, a ring diffuser that delays the air flow and thus builds up pressure. The diffuser ring 19 also serves as a bearing plate for the drive shaft of the electric motor 18 ,

In the embodiment of the compressor according to the invention 1 becomes the upper one in the drawing, that is, that of the compressor head 22 facing part of the flow channel 42 through the first housing part 14 of the compressor and the diffuser ring 19 of the housing 16 formed so that the diffuser ring 19 also through the air in the flow channel 42 can be cooled.

The flow channel is in the device according to the invention 42 (Volute) folded over in the axial direction and thus in the direction of the second housing part 16 of the electric motor 18 aligned. (Usually, the volute is connected above the radial diffuser, but directed towards the suction side, in the case of corresponding compressors of the prior art). The flow channel 42 according to the embodiment of 1 is in the second housing part 16 of the compressor 10 formed, which adjoins the compressor wheel in the axial direction. The second housing part advantageously consists 16 which drives the electric motor driving the compressor 18 surrounds, from a good heat-conducting material. In particular, this housing can be made of a metal, for example aluminum. This housing part comprises the flow channel 42 and a carrier 52 for electronic components 54 (Electronics compartment) of the drive system. The air flowing past in the flow channel 42 cools on the one hand via the diffuser ring 19 the electric motor 18 and also the electronic components 54 in the electronics compartment 52 ,

The flow channel 42 the compressor can be designed in various cross-sectional shapes. An approximately elliptical cross section is advantageous. In the in 1 shown embodiment, there is only a slight difference in the sizes of the semiaxes of the elliptical cross-sectional shape. In other embodiments, the ellipticity can be more pronounced. For example, it is also possible to use the flow channel 42 To be designed and arranged so that the large semi-axis of the ellipse to be inscribed in the channel runs parallel to the drive shaft of the compressor. In this way it is possible for the motor housing 17 large area through the air flow of the flow channel 42 to cool. However, the compressor according to the invention is not based on the use of an elliptical cross-sectional profile for the flow channel 42 limited. Circular or other cross-sectional shapes are also possible.

The drive motor 18 which is a stator 44 as well as one with a drive shaft 46 connected rotor 48 is designed such that the motor has a smaller diameter than the inside diameter of the flow channel 42 has. In this way it is possible that the circumferential direction of the housing 12 running flow channel folded over in the direction of the electric motor 42 the electric motor 18 completely surrounds in the circumferential direction and at least partially encompasses in the axial direction.

The electric motor 18 facing, lower part of the flow channel 42 is in the housing part 15 or 19 worked out. For technical reasons, the housing is 16 trained in several pieces. The housing part 15 also contains the carrier 52 for the electronic components of the motor control. The high air mass flow in the flow channel 42 ensures optimal cooling of the metal body 50 of the housing part 15 , The good thermal conductivity of the metal thus ensures good cooling of the electronics compartment 52 , which is in the second housing part 15 is trained. In addition, the drive motor 18 with its housing 17 , which is in the radial direction from the housing part 15 is also surrounded by the metal body 50 cooled.

Electronic components are advantageous 54 the power electronics for controlling the electric motor 18 or for the operation of the compressor 10 in thermal contact with the metal body 50 appropriate. For this purpose, the electronic components and, in particular, the power semiconductors generating a high power loss can be directly or directly on the housing part, with or without heat conducting means 15 be attached. In this way it is possible to ensure good heat transfer, i.e. a high heat flow from the electronic components 54 in the air that is in the flow channel 42 located to realize. The electronics compartment 52 has a lid 56 , which if necessary. through corresponding openings in its outside 57 can provide additional heat exchange with the environment.

The housing part 17 of the electric motor is, as already described, thermally strong on the diffuser ring 19 and the housing part 15 coupled so that the heat produced by the engine can be dissipated well in this way.

2 and 3 show a compressor only slightly modified with respect to the drive motor 11 , While the compressor is operating 10 respectively. 11 , the electric motor drives 18 via the drive shaft 46 the compressor wheel 30 in the compressor room 28 on. In the embodiment of the 2 and 2 is the housing 1 6 of the compressor 11 one-story training. Although this has manufacturing disadvantages, it ensures optimal cooling of both the motor 18 , as well as the electronic components 54 through the air of the flow channel 42 ,

The adaptation to different mass flows in the active or passive state of the compressor 10 respectively. 11 takes place by means of a control hood 60 that in the first housing part 14 between the inlet port 26 and the compressor room 28 of the compressor is arranged in a bell shape. From the inlet port 26 a bypass channel branches in an almost tangential direction 62 starting from a connection between the inlet duct 24 and the flow channel 42 allows. The bypass channel 62 opens into the outlet circumference of the radial diffuser 40 which at this point is directly in the flow channel 42 transforms.

In the radial diffuser 40 are shovels 64 arranged with the control hood 60 have a mechanical operative connection. In the active state of the compressor 10 or drives the twist radially out of the compressor wheel 30 in the radial diffuser 40 flowing, compressed air the control hood 60 by means of the blades in the diffuser 64 in the direction of rotation of the compressor wheel. The control hood 60 is in the housing 14 stored in such a way that it rotates through the air swirl by a defined angle and thereby the bypass channel 62 by twisting windows 66 or corresponding other locking elements 68 closes. In this case, the compressed air drawn in comes from the inlet connection 26 directly into the compression room 28 , in which it is using the compressor wheel 30 accelerated and thus compressed. Via the flow channel 42 the air goes towards the exhaust duct 43 forwarded. In the compressor according to the invention 10 respectively. 11 both sides of the bypass channel 62 , ie

both the intake duct 24 facing the beginning of the bypass channel 62 , as well as the radial diffuser 40 facing end of the bypass channel 62 through the closing elements 68 or by turning the windows 66 in the control hood 60 locked. In this way it is possible to avoid vortex formation, which could form, for example, at the opening of the bypass channel to the radial diffuser. Such vortex formation represents an increased flow resistance and would have a disadvantageous effect on the desired cheap and thus low-loss flow.

The control hood 60 is in the housing 14 so that they are at a defined angle through the on the blades 64 attacking air swirl rotates while doing a spring device 70 between the control hood 60 and the housing 14 sits, tense.

Is the electric drive 18 of the compressor 10 respectively. 11 switched off, the spring device ensures 70 for a restoring moment that the control hood 60 back in their in 3 shown starting position rotates and thus the closing elements 68 in front of the ends of the bypass channel 62 removed and the bypass channel opens.

3 shows the device according to the invention with the bypass channel open 62 , The compressor air drawn in, for example, by the downstream exhaust gas turbocharger passes through the inlet duct 24 and the first flow channel 36 in the control hood 60 of the compressor according to the invention and from there via the window elements 66 in the now open bypass channel 62 , Due to the large flow cross-section, both in the inlet channel 24 , the window 66 as well as in the bypass channel 62 the air flowing through the passive additional compressor experiences only a slight flow resistance and in turn reaches the flow channel almost unhindered 42 and from there to the outlet 43 of the compressor 10 respectively. 11 , On their way through the flow channel 42 the sucked-in air enables efficient cooling, in particular of the second housing part 16 with the drive motor arranged in it 18 , The compressor 10 respectively. 11 can use the air flowing past in this passive operating mode to bring itself to the lowest possible operating temperature for the next use.

With the device described it is advantageously possible cooling with the help of the intake air of both the driving electric motor and the associated electronics to realize an electrically operated additional compressor without thereby on the fluidic optimal shaping of the flow to dispense with the intake air. In both modes can cheap with this facility and therefore low-loss flows be trained, which in any case to a cheaper efficiency of Internal combustion engine with associated Charge air supply leads. By the arrangement according to the invention one fluidically optimal flow channel Is it possible, even when using a bypass channel in passive operation of the compressor according to the invention optimal cooling maintaining the electronic components of the device preferably greater Flow areas to realize.

The electrically driven according to the invention Charge air compressor is not on the one presented in the drawings embodiment limited. In particular, the device is not limited to use only of a single compressor wheel.

The charge air compressor according to the invention is not limited on the use of a control hood for the integrated bypass channel.

Claims (13)

Electrically operated charge air compressor with a housing ( 12 ), with at least one in a compressor room ( 28 ) of a first housing part ( 14 ) arranged compressor wheel ( 30 ) that flows between an air inlet ( 24 ) and an air outlet ( 43 ) of the housing ( 12 ) is arranged with a the compressor chamber ( 28 ) with the air outlet ( 43 ) connecting, in the circumferential direction of the first housing part ( 12 ) flowing flow channel ( 42 ), as well as with a in a second housing part ( 16 ) of the housing ( 12 ) arranged electric motor ( 18 ) to operate the compressor wheel ( 30 ), characterized in that the flow channel ( 42 ) the electric motor ( 18 ) encompasses at least partially in the axial direction and in thermal connection with the electric motor ( 18 ) and the second housing part ( 16 ), with the second housing part ( 16 ) a diffuser ring ( 19 ) which has a part of the boundary of the flow channel ( 42 ) forms and thermally to the electric motor ( 18 ) is coupled. Electrically operated charge air compressor according to claim 1, characterized in that electronic components ( 54 ), in particular electronic components of the motor electronics of the driving electric motor ( 18 ), such as in the second housing part ( 16 ) that the electronics ( 54 ) mainly via the flow channel ( 42 ) is cooled. Electrically operated charge air compressor according to claim 1 or 2, characterized in that the second housing part ( 16 ) consists at least partially of a heat-conducting material. Electrically operated charge air compressor according to one of claims 1 to 3, characterized in that the flow channel ( 42 ) essentially in the second housing part ( 16 ) is trained. Electrically operated charge air compressor according to claim 4, characterized in that the flow channel ( 42 ) in one piece with the second housing part ( 16 ) is trained. Electrically operated charge air compressor according to one of the preceding claims, characterized in that the flow channel ( 42 ) on the air intake ( 24 ) opposite side of the compressor wheel ( 30 ) is arranged. Electrically operated charge air compressor according to one of the preceding claims, characterized in that the flow channel ( 42 ) one in the circumferential direction of the housing ( 12 ) has a broad cross-section. Electrically operated charge air compressor according to claim 7, characterized in that the flow channel ( 42 ) has an essentially elliptical cross section, the large semiaxis of the ellipse essentially parallel to the drive shaft ( 46 ) of the electric motor ( 18 ) runs. Electrically operated charge air compressor according to one of the preceding claims, characterized in that the flow channel ( 42 ) via a bypass channel ( 62 ), bypassing the compressor wheel ( 30 ), with the air inlet ( 24 ) of the housing ( 12 ) is connectable. Electrically operated charge air compressor according to claim 9, characterized in that in the first housing part ( 14 ) a rotatable control hood ( 60 ) is provided, which is activated when the electric motor ( 18 ) the bypass channel ( 62 ) by turning the corresponding locking elements ( 68 ) closes. Electrically operated charge air compressor according to claim 10, characterized in that the control hood ( 60 ) with blades ( 64 ) in the radial diffuser ( 40 ) are arranged, mechanically effective connected is. Electrically operated charge air compressor according to claim 11, characterized in that the rotation of the control hood ( 60 ) by means of the in the radial diffuser ( 40 ) arranged blades ( 64 ) is air driven. Electrically operated charge air compressor according to one of claims 10 to 12, characterized in that an elastic spring device ( 70 ) is provided, which with the control hood ( 60 ) is operatively connected and the bypass channel ( 62 ) with deactivated electric motor ( 18 ) on the control hood ( 60 ) acting restoring torque opens.